This invention relates to a personal computer (PC) based system used to measure projectile velocity and perform real-time precision triggering of multiple flash X-ray equipment widely used for in-flight diagnostics of ballistics projectiles. This flash X-ray equipment can be located randomly along the flight path of the projectile.
A flash x-ray is like an electronic flash for photography and produces a very intense energy burst in a very short period of time. This allows the photographing of an event which lasts for a very short period of time with x-rays, and also provides the possibility of making images behind opaque objects. In such devices, the x-ray tube is installed in the tube heads. The remote tube head is the most common configuration in a ballistic environment.
Various methods are available for triggering pulsed radiation systems to observe high speed events such as aluminum foil penetration or "Make Screen", or a normally closed foil circuit or "Break Screen." The break screen may be provided by an electrical circuit which is interrupted by the projectile and generates a trigger pulse. This can be made using an etched metallic line on an insulating paper which is interrupted by impact of the projectile.
The standard method of triggering flash x-ray to capture the in-flight projectile on radiographs has been to predict the velocity of the projectile before it is fired and to set up the delay times for triggering the x-ray tubes by delay generators according to this predicted velocity. The entire success of the radiograph thus depends on the accuracy of that velocity prediction. A more advanced system is described in "Development of an Automatic, Velocity-Independent Flash X-Ray Triggering System" by Lindy R. Ford and James D. Moravec, Sr., U.S. Army Yuma Proving Ground, Yuma, AZ, (1986) in 1986 Flash Radiography Topical, The American Society For Nondestructive Testing, Inc., edited by Edwin A. Webster, Jr. and Alfred M. Kennedy, in which flash X-Rays are taken of projectiles which are independent of velocities [which was the problem with prior apparatus]. However, this system did not permit random placement of the stations at which the flash X-rays are taken. It will be seen that the current invention however, allows the x-ray heads to be located randomly at several locations, called action stations, along the flight path of the projectile.